1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD module device.
2. Description of the Related Art
As requirements for displaying of information increases, the demand for flat panel display devices having slim profiles, light weight, and low power consumption increases. The LCD device is one type of flat panel display device that has superior visibility, low power consumption, and low heat radiation, as compared to cathode ray tube (CRT) device having similar screen sizes. Accordingly, the LCD device is commonly used in hand-held terminal devices, computer monitors, and television devices. In addition, plasma display panel (PDP) devices and field emission display (FED) devices are currently being developed as other types of flat panel display devices.
The LCD device includes two facing substrates each having an electrode for generating an electric field, and a liquid crystal layer interposed therebetween. Accordingly, the display of images is controlling by alignment of liquid crystal molecules of the liquid crystal layer using an electric field generated by the electrodes of the two facing substrates.
FIG. 1 is a schematic cross sectional view of an LCD module device according to the related art. In FIG. 1, an LCD module device includes a main frame 14 that receives a backlight assembly for generating and controlling light therein, a panel guide 12 positioned along a horizontal direction on the main frame 14, an LCD panel 2 mounted on the panel guide 12, a bottom case 10 for fixing the main frame 14, and a top case 16 for enclosing edges of the LCD panel 2 and coupled to the bottom case 10. The top case 16 and the bottom case 10 are designed such that their sides mutually overlap, and are affixed at the overlapped portion by a connector.
The backlight assembly includes a lamp housing 18 provided with a lamp 20, a light guide plate 6 for converting linear light emitted from the lamp 20 into surface light, optical sheets 4 disposed on the light guide plate 6 for enhancing an efficiency of the surface light, and a reflector 24 disposed on a rear surface of the light guide plate 6 for reflecting the surface light toward a front side, i.e., toward the LCD panel 2.
The lamp housing 18 is L-shaped and encloses top and side portions of the lamp 20. The reflector 24 is disposed on the rear surface of the light guide plate 6 and extends to a bottom portion of the lamp 20 and contacts one end of the lamp housing 18. In addition, the optical sheets 4 include a stack comprising a diffusion sheet, a prism sheet, and a protection sheet. Furthermore, the main frame 14 includes one of a resin material and a metal material, and affixes and supports the backlight assembly. The panel guide 12 is molded from a resin material, such as polycarbonate, and is attached onto the lamp housing 18 to support a bottom edge portion of the LCD panel 2.
In FIG. 1, the LCD panel 2 includes an upper substrate 11, a lower substrate 13 that opposes the upper substrate 11, and a liquid crystal layer interposed between the upper substrate 11 and the lower substrate 13. Each of the upper substrate 11 and the lower substrate 13 has a polarizing plate attached onto an outer surface thereof. The lower substrate 13 includes a matrix array of gate and data lines, wherein a plurality of pixels and a plurality of thin film transistors (TFTs) that are connected to the pixels are provided at intersection regions of the gate and data lines. Although not explicitly shown in FIG. 1, electrical pads are formed along edge portion of the lower substrate 13 for receiving external signals. The electrical pads are electrically connected to a printed circuit board (PCB) 8 by a tape carrier package (TCP) 22. The PCB 8 is mounted on the main frame 14. In addition, a driving integrated circuit 26, which generates driving signals for driving the gate and data lines of the LCD panel 2 is mounted on the TCP 22. The PCB 8 provides control signals and the driving integrated circuit 26 generates driving signals that are supplied to corresponding ones of the gate/data lines through the electrical pads (not shown) of the LCD panel 2.
FIG. 2 is an enlarged view of region A of FIG. 1 according to the related art. In FIG. 2, the stacked optical sheets 4 wrinkle/distort along a width direction due to excessive amounts of heat or moisture. In most cases, the wrinkles/distortions are generated in the optical sheets 4 within a gap G between the LCD panel 2 and the optical sheets 4. Accordingly, the wrinkles do not permit uniform light to be transmitted through the optical sheets 4. As a result, wrinkled/distorted images are displayed on the LCD panel 2, thereby lowering image quality. In addition, the wrinkles of the optical sheets 4 make edge portions of the displayed images appear darkened.